- #1
Clari
- 62
- 0
Why the energy of 3s electron of Na is much higher than that of the 3p electrons of Cl?
Covalent Bonding: Why Na 3s Electron Energy is Higher than Cl 3p
- Thread starter Clari
- Start date
-
- Tags
- Bonding Covalent bonding
Click For Summary
Discussion Overview
The discussion revolves around the energy levels of the 3s electron of sodium (Na) compared to the 3p electrons of chlorine (Cl). Participants explore the implications of electronegativity on orbital energy levels and the conditions necessary for covalent versus ionic bonding.
Discussion Character
- Technical explanation
- Conceptual clarification
- Debate/contested
Main Points Raised
- One participant notes that a rule of thumb suggests that more electronegative atoms have lower energy atomic orbitals compared to less electronegative atoms, leading to the conclusion that Cl's orbitals are lower than Na's.
- Another participant questions the validity of comparing 3s and 3p orbitals directly, suggesting that they are fundamentally different and should not be compared in this context.
- Some participants assert that the differences in energy levels between the orbitals prevent covalent bonding, citing the need for similar energies as a requirement for such bonding to occur.
- There is a mention of the size of ions potentially influencing energy levels, with a participant expressing uncertainty about the relationship between ion size and energy levels.
- A later reply emphasizes that the symmetry of the orbitals allows for comparison, but reiterates that the significant energy difference still precludes covalent bonding.
Areas of Agreement / Disagreement
Participants express differing views on whether 3s and 3p orbitals can be compared directly. While some agree on the influence of electronegativity on orbital energy, the discussion remains unresolved regarding the appropriateness of comparing different types of orbitals.
Contextual Notes
There are unresolved assumptions regarding the definitions of orbital energy levels and the implications of electronegativity on bonding types. The discussion does not clarify the extent to which ion size affects energy levels.
- #2
gravenewworld
- 1,129
- 27
A simple rule of thumb from inorganic says that when comparing 2 atoms, the atom that is more electronegative will have atomic orbitals lower in energy when compared to another atom of lower electronegativity. Cl- is a lot more electronegative than Na so its orbitals are much lower than Na's atomic orbitals. Sodium chloride is also an ionic bond. If you look at it from a molecular orbital theory viewpoint, if the energies of orbitals are so different than the only bonding interaction that can occur is ionic bonding. In order for covalent bonding to occur you must satisfy 3 rules, proper distance, similar symmetry, and similar energies. While the 3p of the Cl and the 3s of the Na atom have similar symmetries, they do not satisfy the rule for similar energies. Thus no covalent bond can form, only an ionic bond.
- #3
Clari
- 62
- 0
Hello Gravenewworld, thank you very much for your clear explanation.. I understand why the energy of 3s orbital of Na is higher than that os 3s orbital of Cl...though I would like to ask: as 3p is different from 3s...why we can compare them this way..or is it that for elements with higher electronegativity, all their orbitals in the same shell is lower in energy than those atoms with higher energies?
- #4
gravenewworld
- 1,129
- 27
Can you re-word your question? I don't really understand what you are asking.
- #5
ForcesofChaos
- 4
- 0
im not sure by what he said seems to be true but i thought it was also (or) the size of the ions that you looked at when you had elements related. Top left most energetic bottom right least.
wait top right most, bottom left least
wait top right most, bottom left least
- #6
Clari
- 62
- 0
my questoin is "Why the energy of 3s electron of Na is much higher than that of the 3p electrons of Cl?", and you told me that it is because Na has lower electronegativity than Cl...but I suppose 3p is not 3s, so we can't compare them this way, isn't it? 
Last edited:
- #7
gravenewworld
- 1,129
- 27
You can compare 3p orbitals with 3s orbitals because they are similar in symmetry. The question is will the 3pz orbital of the Cl atom and the 3s orbital of the Na atom interact to form a covalent bond? Whether they will form a covalent bond once again comes down to the 3 rules I listed earlier. We already said that they are similar in symmetry, and proper distance is usually never a problem. The reason that the 3pz and the 3s orbital do not interact to form a covalent bond is still because of the differences in energy between the two orbitals. The electronegativity difference is so great that it causes the energy differences between the 3pz and 3s orbitals to still be large, so without similar energies a covalent bond can not form, which is why NaCl forms from ionic bonding.
- #8
Clari
- 62
- 0
I understand now..Thanks~~ ^-^
Similar threads
- · Replies 0 ·
- · Replies 12 ·